Hi, and welcome to Airline Mogul!
I would strongly recommend a Kelowna KFC CV5800 (78pax, 300kn), but the Super 580 looks good too. Start replacing your highest earning An-38 routes with other aircraft to maximize profit, then you can assign the An-38 to new, smaller routes.
There is a complete list of aircraft, but it only contains name and production years. Go to Aircraft > View All Aircraft.
Another great tool is Aircraft Search. This allows you to search for aircraft fitting your needs.
I hope this helped you!